Project Summary: Post-stroke hand impairment is prevalent, persistent, and difficult to treat, with negative impact on functional ability and independence. One way to improve treatment efficacy is to augment therapy with peripheral sensory stimulation. While promising, most modalities of sensory stimulation interfere with natural hand tasks. Thus they are administered prior to therapy, requiring additional time commitment and hindering patient adherence and implementation. Further, effects diminish after stimulation, weakening its potency during therapy. To address limitations of existing sensory stimulation and fully leverage the therapeutic benefits of sensory stimulation, a novel sensory stimulation `TheraBracelet' has been developed: A wristwatch applies imperceptible vibration during task practice to stimulate the sensorimotor cortex neurons for coherent firing during hand tasks, leading to enhanced neural communication and hand function recovery. The objective of this project is to determine if combining TheraBracelet with hand task practice is superior to hand task practice alone in an adequately powered study. The study design is a double-blinded randomized controlled trial. Chronic stroke survivors will undergo a standardized hand task-practice therapy program (3 days/week for 6 weeks) with the TheraBracelet device worn on the paretic wrist. The device will deliver vibration for the treatment group and no vibration for the control group. Double blinding is possible because the treatment vibration is imperceptible. Evaluation will be performed at baseline, 2, 4, and 6 weeks of therapy, and 1 month after. Aim 1: To determine clinical potential of TheraBracelet in improving hand functional recovery. Hypothesis: Improvement of hand motor function will be greater for the treatment than control. Hand function will be assessed using the Wolf Motor Function, Box and Block, and Action Research Arm Tests, along with the quantity/quality of the upper limb use in daily living, abilities for daily activities, and participant feedback. Aim 2: To determine the effects of TheraBracelet on sensorimotor grip control and neural communication. Hypothesis: The treatment will enhance sensorimotor grip control and neural communication for hand grip compared with control. Sensorimotor grip control will be assessed using the well-established biomechanical measure of digit force directional control and efficient scaling of grip force during grip-and-lift. Neural communication for hand grip will be quantified as increase in EEG coherence in the cortical sensorimotor network for grip compared to rest. Secondary analyses will include characterizing the time course of effects and responder analysis. Impact: This research will determine clinical utility and biomarkers of this novel stimulation to guide potential translation. This research is translational as this stimulation is implemented in an aesthetically appealing smartwatch, does not interfere with hand motion, and can be easily integrated in clinical practice. Enhancing hand function should substantially increase stroke survivors' independence and quality of life, and reduce caregiver burden.